Biotransformation of 1,2,3,4,7,8-hexachlorodibenzo-p-dioxin by S. wittichii RW1. Depletion of substrate and production of metabolic intermediates. Symbols: ▪, 1,2,3,4,7,8-hexachlorodibenzo-p-dioxin; □, 3,4,5,6-tetrachlorocatechol; ○, 2-methoxy-3,4,5,6-tetrachlorophenol; •, poisoned control.